Homo sapiens lactate dehydrogenase c (Ldhc) gene expression in cancer cells is regulated by transcription factor Sp1, CREB, and CpG island methylation.
The human testis-specific lactate dehydrogenase c gene (hLdhc) is transcribed only in cells of the germinal epithelium. Recently hLdhc was reported to express in a broad spectrum of tumors with relatively high frequency in lung cancer, melanoma, and breast cancer, and in some prostate cancers. Two melanoma cell lines that express the hLdhc gene, A375M and C81-61, were identified and were used to characterize the hLdhc promoter and explore transcriptional regulation of this gene. A 110-bp core promoter, including a conserved GC box and cyclic adenosine monophosphate-responsive element (CRE), were identified as essential for basal promoter activity. The methylation status of the CpG island (CGI) in the hLdhc core promoter sequence was analyzed in hLdhc-expressing and nonexpressing cells and human prostate tumor tissues. The CGI in 2 cell lines expressing the gene was hypomethylated whereas the DNA from cells that did not express hLdhc was hypermethylated. The role of methylation in regulating this promoter was confirmed by experimental induction of hLdhc transcription with the methylation inhibitor 5'aza-deoxycytidine. Quantitative analyses of the methylation level in the CGI were performed in prostate tumor tissues by pyrosequencing. Overall, these experiments demonstrated that hLdhc expression in cancer cells was regulated by transcription factor Sp1 and CREB and promoter CGI methylation. In addition, these findings suggest the possibility of developing a biomarker for cancer diagnosis/prognosis based on DNA methylation of the Ldhc gene.
Tang
Huanghui
H
Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, IL 60208, USA. h-tang2@northwestern.edu
Goldberg
Erwin
E
D001483:Base Sequence; D045744:Cell Line, Tumor; D018899:CpG Islands / Q000235:genetics*; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics* / Q000378:metabolism; D019175:DNA Methylation; D024202:Electrophoretic Mobility Shift Assay; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
C115163:CREB1 protein, human; D017362:Cyclic AMP Response Element-Binding Protein; D007770:L-Lactate Dehydrogenase; D011494:Protein Kinases; C065999:Sp1 kinase